Add tests and other improvements.

- tests are now run against http://trystack.org
- enable testing with python 3.4
- CloudFilesNotebookManager slipped in with the last commit but it
  wasn't meant to, remove it.
- Keeping track of all the parameters to swiftclient.Connection is a PITA,
  opted to leave that entirely to the user. Configuration is now passed as-it-is from the dict connection_args. I'll update the docs shortly.
- Adapted classes for simpler configuration are still possible.
- Copy TestNotebookManager from IPython source tree and adapt it.
Fix unicode handling.
Close connection after tests have done.

I was address the following warning I get with Python3, but it doesn't
fix it.

sys:1: ResourceWarning: unclosed <socket object at 0x108812048>
Don't display authentication key with debugging info.
Fix list_notebooks
Another big commit

- Added adaptor for OpenStack for openrc.sh-style credentials
- Added adaptor for Rackspace CloudFiles (still with username/password)
- The connection is now fired lazily
- Updated documentation